OK, don't want to add to the stress level, but you asked and I do want to pass along a little voice of experience. In June, I had a liver transplant. Yep, the real deal. Looooong story short: got infected during a blood transfusion 30+ years ago, infection stayed dormant and undiagnosed until a few years ago, then liver started to fail. Luckily and obviously, we caught it in time (at the same hospital; how's that for irony!). But that's not the point.
The point is OneTon is absolutely 100% on the money. Doctors and nurses and the hospital staff can work miracles, but the bottom line is, they are human beings and subject to all the laws of physics and Murphy and life that mess with each and every one of us every day.
Like he said, always have a trusted backup buddy or family member with you. Not because you're facing something scary and tricky,

it just makes for good common sense. To the staff, no matter how special they make you feel, you are an item on the shelf, another truck on the lot to be spiffed up, sold and moved out of the way for the next one.
Question everything, every diagnosis, every prescription, every dosage, every time they give you a drug, take a sample or begin a test or procedure. Keep asking why. Why am I getting or doing this? Am I supposed to get this now? Did the doctor say this was OK? Please explain to me again why you are prescribing or doing this? Be polite but firm. Take notes. Make sure they are doing what they said they would do when they said they would do it. And don't let the staff slack off on you. If somebody screws up, let the supervisor know about it, and if they don't respond accordingly, kick it up another notch. You (or, hopefully, your insurance) might be paying for it, but ultimately you are responsible for your own health care.
Having said all that, no worries. I know two people who have done the colon thing and everything was

.